Failure Avoidance in Microelectronics Due to Coefficient of Thermal Expansion (CTE) Mismatch of Substrates and Adhesives

The reliability of electronic packages is of paramount concern in todays electronics industry, and ensuring their thermomechanical integrity is necessary to achieve this reliability. However, this task has become more challenging with miniaturization and the introduction of new materials. Thermal stresses in electronic packages continue to be one of the leading causes of device failure. The proposed project will enable the selection of adhesive/substrate combinations to reduce thermomechanical stresses arising from mismatch between the substrates and adhesives while including the effect of design geometry. Thus, it will identify failure modes due to geometric and material discontinuities such as corners of dissimilar materials under harsh environments. The proposed project will employ the nonlocal peridynamic (PD) theory to predict stress and strain fields as well the failure modes in electronic packages subjected to thermal and moisture loading. The PD methodology overcomes the weaknesses of the existing methods, and it is capable of identifying all of the failure modes without simplifying assumptions. It effectively predicts complex failure modes in electronic packages under general dynamic and static loading conditions. This methodology will enable the selection of appropriate substrate and adhesive combinations so that the process parameters will not adversely impact the substrate/adhesive system. Approved for Public Release 15-MDA-8161 (11 March 15)